The best way to measure any part of DIY ejuice is by percentages. That way you can scale the recipe up or down depending on the amount desired.
Most Flavor Apprentice flavors are not "stand-alone" flavors; you need to combine them in various way to achieve a good
juice. Creams and vanillas and sweeteners are your best friend; even if you don't think you want a creamy-tasting
juice, those are "bottom notes," which make the top notes really pop.
If your combined flavors come to less than 20% of your ejuice, you will probably have to steep (age) it for a pretty long time for it taste like anything at all. If your combined flavors are 20%-30% of the total mix, you may not have to steep, or maybe only for a few hours instead of weeks. That way you know if the mix is good without having to wait around with your thumb in a certain orifice.
The Flavor Apprentice thread is an excellent place to learn, get new recipes, and all kinds of amazing stuff.
Andria